R-7 Semyorka and its variants used as launchers in the early Soviet space program

The R-7 family of rockets (Russian: Р-7) is a series of rockets, derived from the Soviet R-7 Semyorka, the world's first ICBM (Intercontinental ballistic missile). More R-7 rockets have been launched than any other family of large rockets.

Under the direction of the rocket pioneer Sergey Korolyov, the Soviet Union during the 1950s developed an intercontinental ballistic missile (ICBM) that was capable of delivering a heavy nuclear weapon to American targets. That ICBM, called the R-7 or Semyorka (“Number 7”), was first successfully tested on August 21, 1957. Because Soviet nuclear warheads were based on a heavy design, the R-7 had significantly greater weight-lifting capability than did initial U.S. ICBMs. When used as a space launch vehicle, this gave the Soviet Union a significant early advantage in the weight that could be placed in orbit or sent to the Moon or nearby planets. There have been a number of variants of the R-7 with an upper stage, each with a different name, usually matching that of the payload, and each optimized to carry out specific missions. An unmodified R-7 was used to launch the first Soviet satellite, Sputnik 1, on October 4, 1957, and an R-7 variant, the Vostok, launched the first Soviet cosmonauts, among them Yuri Gagarin, who on April 12, 1961, became the first human to orbit Earth. Other variants include the Voshkod, used to launch reconnaissance satellites, and the Molniya, used to launch communications satellites. A multipurpose variant, the Soyuz, was first used in 1966 and, with many subsequent variants and improvements, is still in service. This family of launch vehicles has carried out more space launches than the rest of the world’s launch vehicles combined.

When Soviet nuclear warheads became lighter, the R-7 turned out to be impractical as a ballistic missile, and there were no other heavy payloads with a military application. However, long-term development has made the rockets useful in the Soviet, and later, Russian space programmes. Their purpose shifted primarily to launching satellites, probes, crewed and uncrewed spacecraft, and other non-threatening payloads. The R-7 family consists of both missiles and orbital carrier rockets. Derivatives include the Vostok, Voskhod and Soyuz rockets, which as of 2022 have been used for all Soviet, and later Russian human spaceflights. The type has a unique configuration where four break-away liquid-fueled engines surround a central core. The core acts as, in effect, a "second stage" after the other four engines are jettisoned. These rockets are expendable.

Later modifications were standardised around the Soyuz design. The Soyuz-2 is currently in use.

The Soyuz-FG was retired in 2019 in favour of the Soyuz-2.1a.^[1] R-7 rockets are launched from the Baikonur Cosmodrome, Plesetsk Cosmodrome, Guiana Space Centre (from 2011 to 2022, see Soyuz at the Guiana Space Centre), and the Vostochny Cosmodrome (first launch 2016).

Summary of variants

All the R-7 family rockets are listed here by date of introduction. Most of the early R-7 variants have been retired. Active versions (as of 2022) are shown in green.

Korolev Cross

Korolev cross, Soyuz TMA-04M

The Korolev Cross is a visual phenomenon observed in the smoke plumes of the R-7 series rockets during separation of the four liquid-fueled booster rockets attached to the core stage.^[4] As the boosters fall away from the rocket, they pitch over symmetrically due to aerodynamic forces acting upon them, forming a cross-like shape behind the rocket. The effect is named after Sergei Korolev, the designer of the R-7 rocket. When the rocket is launched into clear skies, the effect can be seen from the ground at the launch site.